1. Field of the Invention
This invention relates to a storage surface assembly for use as a shelf for holding storage items in industrial/commercial applications/environments.
2. Background of the Related Art
Storage shelves used in an industrial/commercial environment must often beat heavy loads while still maintaining their structural integrity, as well as resist the twisting and buckling forces generated when storage items are loaded, unloaded, or moved. These industrial storage shelves are also subjected to fire codes requiring some amount of “open area” along the surface of the shelf, dictated in most cases by the particular environment in which they will be used, as well as the types of items to be stored.
The “open area” required by fire codes is typically 50% of the surface area of the shelf. This open area requirement was imposed to allow a fire in the storage area to be more efficiently contained and extinguished, thus minimizing damage to storage items. More specifically, a shelf with an adequate amount of open area allows a fire initiated on a lower shelf to move vertically up the storage rack, towards the sprinkler, allowing heat to dissipate more quickly and activating the sprinklers before the fire has gained significant intensity. Closed shelves (shelves with little to no open area), which may provide adequate load capacity and structural integrity, would, on the other hand, form an enclosed space between shelves, allowing a fire to build in intensity in that enclosed space, spread horizontally to a neighboring rack of shelves, and also delay deployment of the sprinkler system, rendering the sprinkler system significantly less effective in containing and extinguishing the fire. This 50% open area requirement poses a unique challenge in providing shelves with adequate structural integrity at a reasonable cost, while still meeting this open area requirement. Current solutions, such as those discussed below, are not adequate.
Slatted wooden decking, although easily and inexpensively manufactured, has significant disadvantages in that it is less durable and more susceptible to deformation than steel, and more likely to break under continued loading or changing environmental conditions. Its most significant disadvantage is that it is highly flammable.
Wire mesh decking is a commonly used shelving solution in industrial/commercial applications. Wire mesh meets the 50% open area requirement, but, as wire mesh is simply laid across a series of cross bars, it remains unsupported across a majority of its load-bearing surface, and thus deforms easily. Further, if one of the support bars is damaged, it cannot be repaired or replaced without removal of the entire wire mesh, most likely resulting in replacement of the entire deck as repair would not be cost effective. Additionally, due to the nature of the surface of wire mesh, especially after it has deformed, it is difficult to load/unload/move storage items without damaging the storage items and/or the wire mesh, as the mesh tends to catch on the storage items, producing rips, punctures, or impressions. Wire mesh decks are not easily manufactured or shipped, making them a more costly, less efficient shelving solution.
U.S. Pat. No. 5,279,431 to Highsmith et al. discloses a storage rack with storages surfaces formed by crossbars with tangs extending from the ends which are then inserted into corresponding slots in the side beams. However, Highsmith's design is complicated, difficult and costly to manufacture, and the shelving system must be used with Highsmith's racking system and cannot be readily adapted for use in other racking systems. Further, as the bulk of the load on the storage surface is carried by a very small tang at the end of the crossbar, Highsmith's design cannot be used in commercial/industrial applications, where shelves must beat heavy loads while maintaining their structural integrity.
Likewise, U.S. Pat. No. 5,628,415 to Mulholland also discloses a storage rack with safety bars fitted to support beams by mating tabs and slots. Mulholland's design is complicated, difficult and costly to manufacture, and is for an entire racking system whose shelves cannot be readily adapted for use with other racking systems.
U.S. Pat. No. 5,199,582 to Halstrick discloses a storage rack which uses a corrugated plate to form each shelf Although Halstrick's design incorporates holes in the corrugated sheet to allow for a very limited amount of open area, this design could not meet the 50% open area requirement with out affecting the structural integrity of the shelf.
U.S. Pat. No. 6,401,944 to Kircher et al. discloses a storage rack similar to Halstrick's which does meet the 50% open area requirement. However, there are several disadvantages associated with Kircher's design. Kircher's corrugated deck is expensive to manufacture and ship, increasing cost to the user. If not properly secured in the rack, the deck elements can spread over time due to the load applied by the storage items, forcing the rack to carry more that its design load, thereby compromising the rack's structural integrity. Similar to wire mesh, the holes, unless properly finished, tend to shred storage items when they are loaded, unloaded and moved.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.